Re- design of a multipurpose snowmobile sled for Norwegian volunteer (SAR organizations)

Abstract

"This master thesis is written for Norwegian volunteer organization “Hjelpekorpset” that is a search and rescue organization. The organization performs different kinds of activities in addition to rescue missions. During wintertime, they transport materials, furniture and other cargo to local huts to raise funds for the organization. This is the basis for the thesis, where the aim was to redesign a multipurpose snowmobile sled for both rescue missions and transportations jobs. Problem areas have been the towbar and the general design in terms of securing both stretchers and cargo. The towbar have been reinforced by simplifying the design using fewer components and installing hingejoints in the transmission to the sled. Material selection was done for the towbar rods and the top plate. This resulted in Aluminium alloy Al 6061 on the towbar, the supporting bod structure and the railings, and Plywood for the top plate. After conducting Finite Element Analysis on the system, the attachment ring is performed in a different, stronger material than the rest of the towbar; Titanium Alloy Ti-6Al-2Sn-2Zr-2Mo-2Cr. The design of the railings were altered so that they covers the two longitudinal sides, making it more convenient to secure a stretcher on the sled. A frame was designed that can be attached when needed to make it easier to transport cargo on the sled. Objectives have been to strengthen the towbar and keeping the mass below 50 kg. This have been achieved with a thorough design process ending up on a final weight of the sled of 40 kg. Aesthetics of the design was examined by 3D printing a prototype of the sled approximately 8% of the original dimensions."